The present invention relates to a heat transferable inked ribbon for providing a pressure transferable laminate, and more particularly to a heat transferable inked ribbon for use in heat transfer printing devices, e.g., printers, typewriters or word-processors, which is efficiently and effectively transferred onto a sheet or film with release properties and poor wetting properties upon application of heat to provide a composite laminate, which is transferred from the sheet or film onto an article upon application of pressure.
Heat transfer printing devices like printers, typewriters, or word-processors have been developed and widely applied to individual and office use. In such printing devices, as specific heat elements on a thermal head are heated, part of a thermoplastic ink layer of an inked ribbon corresponding to the specific heat elements softens and is transferred onto a sheet of paper or film. Here, the thermoplastic ink layer is in contact with the heat elements of the thermal head via a heat transferable ribbon base.
A general heat transferable ribbon includes a base or support coated with a thermoplastic ink layer, which contains a colorant and a binder mainly composed of wax. The general inked ribbon is transferred only onto ordinary printing or typing paper upon application of heat.
The owner of this invention has already disclosed an improved heat transferable inked ribbon, which is transferred onto a sheet or film with release properties and poor wetting properties as well as onto an ordinary sheet, in Japanese Published Unexamined Patent Application No. Sho-61-275538, No. Sho-61-275539 and No. Sho-62-85350, and also disclosed a heat transferable inked ribbon with improved heat sensitivity in Japanese Published Unexamined Patent Application No. Sho-62-80126.
In a general heat transfer system, as a thermal head moves, ribbon is continuously drawn out from a ribbon cassette by friction between an ink layer of the ribbon and a printing sheet and is wound up in due course.
The surface of a sheet or film with release properties and poor wetting properties has small friction and may thus not give sufficient forces to draw out and feed a ribbon. In this case, the ribbon is not sufficiently fed and the head strikes the same part of the ribbon many times; in other words, the head slips on the ribbon. On the other hand, when only a small force is required for drawing out the ribbon, the ribbon is not stretched sufficiently and thus does not run straight. The force for drawing out the ribbon varies depending on storage conditions including temperature and period.
Also already disclosed is a heat transferable inked ribbon, which is unchangeably and stably stored and runs straight without causing a slip in a printing device, in Japanese Published Unexamined Patent Applications No. Sho-62-255761, No. Sho-62-255762, No. Sho-62-262348 and No. Sho-62-297155.
The heat transferable inked ribbon is generally transferred onto a white sheet, where only a low hiding power is required. However, when the inked ribbon is transferred onto a sheet or film of various properties and colors to provide a pressure transferable laminate, a high hiding power is required. The hiding power of colorants except black is not sufficiently high, and hence a transferred image does not have a sufficient hiding power, either; that is, the transferred image on the sheet is not clear. No prior publications have dealt with inked ribbons from this aspect.
One objective of the invention is accordingly to provide an improved heat transferable inked ribbon for preparing a pressure transferable laminate.
Another objective of the invention is to provide a heat transferable inked ribbon which is effectively and efficiently transferred onto a sheet or film with poor wetting properties to form a pressure transferable laminate.
A further objective of the invention is to provide a heat transferable inked ribbon, wherein the heat transferred image or composite laminate is easily and completely transferred from a sheet or film onto an article upon application of pressure.
Another important objective of the invention is to provide a heat transferable inked ribbon which is easily stored and maintained.
Still another objective of the invention is to provide a heat transferable inked ribbon which runs straight without causing slipping when used in a printing device.
A still further objective of the invention is to provide a heat transferable inked ribbon which is efficiently and firmly transferred onto a sheet or film even when the colorant used has a small hiding power.